---
_id: '64129'
abstract:
- lang: eng
  text: <jats:p>Selecting scan angles such that surface segments are aligned with
    straight X-ray paths (i.e., rays are tangential to the surface and therefore perpendicular
    to the local surface normal) is known to produce sharper transitions of those
    surface segments in the reconstructed volume. This enhances dimensional accuracy
    in sparse-view computed tomography (CT). However, existing approaches offer no
    direct means to exploit this criterion for automatic scan-angle optimization.
    We propose a method that uses a virtual representation of the CT setup, including
    an STL surface model of the inspected part, to automatically identify taskspecific
    scan angles. Using elementary vector calculus, the algorithm determines projection
    directions that generate tangential X-rays for targeted surface segments. To support
    different levels of geometric complexity, we introduce two variants of the angle-selection
    procedure. The methods were experimentally validated on two objects with distinct
    absorption and geometric characteristics. For a steel gauge block, employing the
    minimum number of task-specific projections required for surface-data completeness
    substantially outperformed a conventional high-projection scan. For a geometrically
    more complex test object, surface-related errors were still reduced within the
    region of interest. The proposed approach – particularly suited for flat surface
    structures and not accounting for image-degrading factors other than cone-beam
    artifacts – shows promise for high-throughput dimensional metrology of mono-material
    parts.</jats:p>
author:
- first_name: Lorenz
  full_name: Butzhammer, Lorenz
  last_name: Butzhammer
- first_name: Matthias Robert Oskar
  full_name: Braun, Matthias Robert Oskar
  last_name: Braun
- first_name: Colin
  full_name: Herath, Colin
  last_name: Herath
- first_name: Tino
  full_name: Hausotte, Tino
  last_name: Hausotte
citation:
  ama: 'Butzhammer L, Braun MRO, Herath C, Hausotte T. Higher accuracy with fewer
    projections? Automated scan angle selection for dimensional Computed Tomography
    based on a simple data completeness measure for the part surface. In: <i>E-Journal
    of Nondestructive Testing</i>. Vol 31. NDT.net GmbH &#38; Co. KG; 2026. doi:<a
    href="https://doi.org/10.58286/32560">10.58286/32560</a>'
  apa: Butzhammer, L., Braun, M. R. O., Herath, C., &#38; Hausotte, T. (2026). Higher
    accuracy with fewer projections? Automated scan angle selection for dimensional
    Computed Tomography based on a simple data completeness measure for the part surface.
    <i>E-Journal of Nondestructive Testing</i>, <i>31</i>(3). <a href="https://doi.org/10.58286/32560">https://doi.org/10.58286/32560</a>
  bibtex: '@inproceedings{Butzhammer_Braun_Herath_Hausotte_2026, title={Higher accuracy
    with fewer projections? Automated scan angle selection for dimensional Computed
    Tomography based on a simple data completeness measure for the part surface},
    volume={31}, DOI={<a href="https://doi.org/10.58286/32560">10.58286/32560</a>},
    number={3}, booktitle={e-Journal of Nondestructive Testing}, publisher={NDT.net
    GmbH &#38; Co. KG}, author={Butzhammer, Lorenz and Braun, Matthias Robert Oskar
    and Herath, Colin and Hausotte, Tino}, year={2026} }'
  chicago: Butzhammer, Lorenz, Matthias Robert Oskar Braun, Colin Herath, and Tino
    Hausotte. “Higher Accuracy with Fewer Projections? Automated Scan Angle Selection
    for Dimensional Computed Tomography Based on a Simple Data Completeness Measure
    for the Part Surface.” In <i>E-Journal of Nondestructive Testing</i>, Vol. 31.
    NDT.net GmbH &#38; Co. KG, 2026. <a href="https://doi.org/10.58286/32560">https://doi.org/10.58286/32560</a>.
  ieee: 'L. Butzhammer, M. R. O. Braun, C. Herath, and T. Hausotte, “Higher accuracy
    with fewer projections? Automated scan angle selection for dimensional Computed
    Tomography based on a simple data completeness measure for the part surface,”
    in <i>e-Journal of Nondestructive Testing</i>, Linz, 2026, vol. 31, no. 3, doi:
    <a href="https://doi.org/10.58286/32560">10.58286/32560</a>.'
  mla: Butzhammer, Lorenz, et al. “Higher Accuracy with Fewer Projections? Automated
    Scan Angle Selection for Dimensional Computed Tomography Based on a Simple Data
    Completeness Measure for the Part Surface.” <i>E-Journal of Nondestructive Testing</i>,
    vol. 31, no. 3, NDT.net GmbH &#38; Co. KG, 2026, doi:<a href="https://doi.org/10.58286/32560">10.58286/32560</a>.
  short: 'L. Butzhammer, M.R.O. Braun, C. Herath, T. Hausotte, in: E-Journal of Nondestructive
    Testing, NDT.net GmbH &#38; Co. KG, 2026.'
conference:
  location: Linz
  name: 15th Conference on Industrial Computed Tomography (iCT)
date_created: 2026-02-12T10:11:08Z
date_updated: 2026-02-12T10:41:45Z
department:
- _id: '630'
doi: 10.58286/32560
intvolume: '        31'
issue: '3'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://www.ndt.net/article/ctc2026/papers/ict26_Contribution_184.pdf
oa: '1'
project:
- _id: '130'
  name: 'TRR 285:  Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen
    Prozessketten'
- _id: '133'
  name: TRR 285 - Project Area C
- _id: '149'
  name: TRR 285 - Subproject C05
publication: e-Journal of Nondestructive Testing
publication_identifier:
  issn:
  - 1435-4934
publication_status: published
publisher: NDT.net GmbH & Co. KG
quality_controlled: '1'
status: public
title: Higher accuracy with fewer projections? Automated scan angle selection for
  dimensional Computed Tomography based on a simple data completeness measure for
  the part surface
type: conference
user_id: '93720'
volume: 31
year: '2026'
...
---
_id: '64861'
abstract:
- lang: eng
  text: <jats:p>In-situ computed tomography (CT) experiments on materials with time-dependent
    mechanical behaviour are affected by relaxationinduced motion, which can lead
    to image blur and motion-related artefacts if scans are initiated before relaxation-induced
    motion has subsided. Scan start times are therefore commonly defined based on
    force relaxation or force-gradient criteria, although these signals do not directly
    quantify image-relevant specimen motion. In this work, a radiography-based approach
    is presented to estimate relaxation-induced motion via pixel shifts from projection
    images acquired prior to CT scans. These projection-based pixel shift estimates
    of relaxation-induced motion are related to scan-specific image blur observed
    in the reconstructed volumes. Thereby, a direct link between specimen motion during
    the scan and CT image quality is established. The method is demonstrated for thermo-mechanically
    loaded specimens with pronounced temperature-dependent material behaviour, where
    relaxation-induced motion persists over extended time scales. The results show
    that projection-based pixel shift estimation provides a physically meaningful
    and experimentally accessible basis for defining scan start criteria. CT acquisition
    can be initiated based on an allowable level of relaxation-induced motion, rather
    than waiting for mechanical equilibrium to be reached. The proposed approach therefore
    offers a direct, image-related framework for scan timing in in-situ CT experiments
    on time-dependent materials.</jats:p>
author:
- first_name: Alrik
  full_name: Dargel, Alrik
  last_name: Dargel
- first_name: Juliane
  full_name: Troschitz, Juliane
  last_name: Troschitz
- first_name: Maik
  full_name: Gude, Maik
  last_name: Gude
- first_name: Robert
  full_name: Kupfer, Robert
  last_name: Kupfer
citation:
  ama: 'Dargel A, Troschitz J, Gude M, Kupfer R. In-situ CT of Viscoelastic Plastic
    Materials: A Radiography-Based Lead Time Determination for Composite–Metal Joints
    at Elevated Temperature. <i>e-Journal of Nondestructive Testing</i>. 2026;31(3).
    doi:<a href="https://doi.org/10.58286/32601">10.58286/32601</a>'
  apa: 'Dargel, A., Troschitz, J., Gude, M., &#38; Kupfer, R. (2026). In-situ CT of
    Viscoelastic Plastic Materials: A Radiography-Based Lead Time Determination for
    Composite–Metal Joints at Elevated Temperature. <i>E-Journal of Nondestructive
    Testing</i>, <i>31</i>(3). <a href="https://doi.org/10.58286/32601">https://doi.org/10.58286/32601</a>'
  bibtex: '@article{Dargel_Troschitz_Gude_Kupfer_2026, title={In-situ CT of Viscoelastic
    Plastic Materials: A Radiography-Based Lead Time Determination for Composite–Metal
    Joints at Elevated Temperature}, volume={31}, DOI={<a href="https://doi.org/10.58286/32601">10.58286/32601</a>},
    number={3}, journal={e-Journal of Nondestructive Testing}, publisher={NDT.net
    GmbH &#38; Co. KG}, author={Dargel, Alrik and Troschitz, Juliane and Gude, Maik
    and Kupfer, Robert}, year={2026} }'
  chicago: 'Dargel, Alrik, Juliane Troschitz, Maik Gude, and Robert Kupfer. “In-Situ
    CT of Viscoelastic Plastic Materials: A Radiography-Based Lead Time Determination
    for Composite–Metal Joints at Elevated Temperature.” <i>E-Journal of Nondestructive
    Testing</i> 31, no. 3 (2026). <a href="https://doi.org/10.58286/32601">https://doi.org/10.58286/32601</a>.'
  ieee: 'A. Dargel, J. Troschitz, M. Gude, and R. Kupfer, “In-situ CT of Viscoelastic
    Plastic Materials: A Radiography-Based Lead Time Determination for Composite–Metal
    Joints at Elevated Temperature,” <i>e-Journal of Nondestructive Testing</i>, vol.
    31, no. 3, 2026, doi: <a href="https://doi.org/10.58286/32601">10.58286/32601</a>.'
  mla: 'Dargel, Alrik, et al. “In-Situ CT of Viscoelastic Plastic Materials: A Radiography-Based
    Lead Time Determination for Composite–Metal Joints at Elevated Temperature.” <i>E-Journal
    of Nondestructive Testing</i>, vol. 31, no. 3, NDT.net GmbH &#38; Co. KG, 2026,
    doi:<a href="https://doi.org/10.58286/32601">10.58286/32601</a>.'
  short: A. Dargel, J. Troschitz, M. Gude, R. Kupfer, E-Journal of Nondestructive
    Testing 31 (2026).
date_created: 2026-03-06T10:19:09Z
date_updated: 2026-03-06T10:22:21Z
ddc:
- '620'
doi: 10.58286/32601
file:
- access_level: closed
  content_type: application/pdf
  creator: adargel
  date_created: 2026-03-06T10:20:14Z
  date_updated: 2026-03-06T10:20:14Z
  file_id: '64862'
  file_name: ict26_Contribution_227.pdf
  file_size: 10028899
  relation: main_file
  success: 1
file_date_updated: 2026-03-06T10:20:14Z
has_accepted_license: '1'
intvolume: '        31'
issue: '3'
language:
- iso: eng
publication: e-Journal of Nondestructive Testing
publication_identifier:
  issn:
  - 1435-4934
publication_status: published
publisher: NDT.net GmbH & Co. KG
status: public
title: 'In-situ CT of Viscoelastic Plastic Materials: A Radiography-Based Lead Time
  Determination for Composite–Metal Joints at Elevated Temperature'
type: journal_article
user_id: '114764'
volume: 31
year: '2026'
...
---
_id: '51192'
abstract:
- lang: eng
  text: "<jats:p>\r\nDestructive micrograph analysis (MA) is the standard method for
    the assessment of clinched joints. However, during the joint preparation for the
    MA, geometric features of the joint can change due to elastic effects and closing
    cracks. X-ray computed tomography (CT) is a promising alternative to investigate
    the joint non-estructively. However, if the material properties of similar joining
    partners are the same, the CT is not able to correctly resolve surfaces in the
    joint that are close to or pressing onto each other. These surfaces are relevant
    for the determination of characteristic dimensions such as neck thickness and
    undercut. By placing a thin, highly radiopaque tin layer between the joining partners,
    the interfacial area in the reconstructed volume can be highlighted. In this work,
    a method for the localisation of the tin layer inside the joint as well as threshold
    value procedures for the outer joint contour in cross section images are investigated.
    The measured characteristic dimensions are compared with measured values from
    MA of the same samples and of samples without tin layer. In addition, possible
    effects of the tin layer on the joining point characteristics as well as problems
    of the MA are discussed.\r\n</jats:p>"
author:
- first_name: Matthias
  full_name: Busch, Matthias
  last_name: Busch
- first_name: Daniel
  full_name: Köhler, Daniel
  last_name: Köhler
- first_name: Tino
  full_name: Hausotte, Tino
  last_name: Hausotte
- first_name: Robert
  full_name: Kupfer, Robert
  last_name: Kupfer
- first_name: Juliane
  full_name: Troschitz, Juliane
  last_name: Troschitz
- first_name: Maik
  full_name: Gude, Maik
  last_name: Gude
citation:
  ama: Busch M, Köhler D, Hausotte T, Kupfer R, Troschitz J, Gude M. Approach to Determine
    the Characteristic Dimensions of Clinched Joints by Industrial X-ray Computed
    Tomography. <i>e-Journal of Nondestructive Testing</i>. 2022;27(12). doi:<a href="https://doi.org/10.58286/27519">10.58286/27519</a>
  apa: Busch, M., Köhler, D., Hausotte, T., Kupfer, R., Troschitz, J., &#38; Gude,
    M. (2022). Approach to Determine the Characteristic Dimensions of Clinched Joints
    by Industrial X-ray Computed Tomography. <i>E-Journal of Nondestructive Testing</i>,
    <i>27</i>(12). <a href="https://doi.org/10.58286/27519">https://doi.org/10.58286/27519</a>
  bibtex: '@article{Busch_Köhler_Hausotte_Kupfer_Troschitz_Gude_2022, title={Approach
    to Determine the Characteristic Dimensions of Clinched Joints by Industrial X-ray
    Computed Tomography}, volume={27}, DOI={<a href="https://doi.org/10.58286/27519">10.58286/27519</a>},
    number={12}, journal={e-Journal of Nondestructive Testing}, publisher={NDT.net},
    author={Busch, Matthias and Köhler, Daniel and Hausotte, Tino and Kupfer, Robert
    and Troschitz, Juliane and Gude, Maik}, year={2022} }'
  chicago: Busch, Matthias, Daniel Köhler, Tino Hausotte, Robert Kupfer, Juliane Troschitz,
    and Maik Gude. “Approach to Determine the Characteristic Dimensions of Clinched
    Joints by Industrial X-Ray Computed Tomography.” <i>E-Journal of Nondestructive
    Testing</i> 27, no. 12 (2022). <a href="https://doi.org/10.58286/27519">https://doi.org/10.58286/27519</a>.
  ieee: 'M. Busch, D. Köhler, T. Hausotte, R. Kupfer, J. Troschitz, and M. Gude, “Approach
    to Determine the Characteristic Dimensions of Clinched Joints by Industrial X-ray
    Computed Tomography,” <i>e-Journal of Nondestructive Testing</i>, vol. 27, no.
    12, 2022, doi: <a href="https://doi.org/10.58286/27519">10.58286/27519</a>.'
  mla: Busch, Matthias, et al. “Approach to Determine the Characteristic Dimensions
    of Clinched Joints by Industrial X-Ray Computed Tomography.” <i>E-Journal of Nondestructive
    Testing</i>, vol. 27, no. 12, NDT.net, 2022, doi:<a href="https://doi.org/10.58286/27519">10.58286/27519</a>.
  short: M. Busch, D. Köhler, T. Hausotte, R. Kupfer, J. Troschitz, M. Gude, E-Journal
    of Nondestructive Testing 27 (2022).
date_created: 2024-02-06T14:59:06Z
date_updated: 2025-06-02T20:19:07Z
department:
- _id: '157'
- _id: '43'
doi: 10.58286/27519
intvolume: '        27'
issue: '12'
language:
- iso: eng
project:
- _id: '130'
  grant_number: '418701707'
  name: 'TRR 285: TRR 285'
- _id: '133'
  name: 'TRR 285 - C: TRR 285 - Project Area C'
- _id: '148'
  name: 'TRR 285 – C04: TRR 285 - Subproject C04'
- _id: '149'
  name: 'TRR 285 – C05: TRR 285 - Subproject C05'
publication: e-Journal of Nondestructive Testing
publication_identifier:
  issn:
  - 1435-4934
publication_status: published
publisher: NDT.net
status: public
title: Approach to Determine the Characteristic Dimensions of Clinched Joints by Industrial
  X-ray Computed Tomography
type: journal_article
user_id: '83408'
volume: 27
year: '2022'
...